Does comorbid substance use disorder exacerbate borderline personality features? A comparison of borderline personality disorder individuals with vs. without current substance dependence.

There is compelling evidence that comorbid borderline personality disorder (BPD) negatively impact the clinical courses and outcomes of substance use disorders (SUD). Conversely, there is little evidence that concurrent SUD exacerbates the clinical characteristics of BPD. Thus, this study sought to examine whether the presence of current substance dependence among BPD patients would be associated with stronger BPD-relevant personality traits and behavioral characteristics. Female BPD patients without (BOR; n = 37) or with current substance dependence (BSUD; n = 19), and female non-BPD/SUD controls (CON; n = 48) were compared with respect to impulsivity, affective lability, affective intensity, externalizing behaviors, and self-harming/suicidal tendencies, taking into consideration their comorbid mood disorders, anxiety disorders, and antisocial personality disorder. Results indicated that both BOR and BSUD groups scored higher than CON in most of the measures, but BOR and BSUD failed to reveal significant group differences especially when the influence of comorbid psychopathology was removed. The overall pattern of findings remained identical even when comparing BPD patients with versus without the diagnosis of lifetime substance dependence. Our results do not support the notion that BPD individuals with SUD display more severe BPD features than individuals with BPD alone.